It has been known in the art to provide a removable cover or shield for protecting the front end of a vehicle from impact damage due to flying road debris. Covers of both rigid and flexible construction have been known. For example, U.S. Pat. No. 4,376,546 to Guccione et al. discloses a vehicle front end shield constructed of either one or two panels of rigid, hard plastic, such as PVC which conform to the contours of the exterior surface of the vehicle. The panels are supported spaced slightly above the surface of the vehicle by a soft spacer element which may take the form of a continuous peripheral resilient bead, thereby preventing the cover from contacting the surface to avoid scratching and discoloration due to leaching. While providing excellent mechanical protection, such rigid covers are expensive to manufacture due to both tooling and material costs. They are also bulky and difficult to store compactly. While the storage problem can, to some extent, be overcome by forming the cover in multiple pieces, doing so interrupts the smooth contours essential to an attractive appearance and complicates installation and removal of the cover.
A flexible automobile bra is described in U.S. Pat. No. 4,219,218 to Waldon. That bra consists of a body having an exterior vinyl layer backed with a foam or felt lining on its underside. The bra is draped over the front end of a car and secured to its exterior surface by a series of fasteners which engage the automobile at various locations, such as the undersides of the fender wells and bumper. Flexible bras of such a construction do offer a degree of protection against chips and scratches from small flying objects. However, such covers themselves can also seriously damage an automobile's finish.
Because they directly contact the surface of an automobile, moisture from rain or ambient humidity becomes trapped between the underside of the bra and the automobile's finish. Since modern automobile finishes are highly impervious to water, trapped moisture alone does not normally damage the finish. However, sunlight impinging on the exterior of the cover can cause a build up of heat beneath the bra which can cause a temperature rise large enough that moisture trapped against the surface of the car approaches or even exceeds the boiling point. Under such conditions, the automobile's surface finish can be literally "cooked" causing discoloration, loss of adhesion and/or blistering.
Another problem which has plagued flexible automobile bras in the past is that they have a tendency to flap and beat against the automobile's finish especially when driving under high speed or windy conditions. Within a very short time, such flapping can abrade the automobile's surface finish, no matter how soft the material on the underside of the bra. This is particularly true when even a small amount of dirt is present under the bra.
It has also been known to provide rigid automobile protective covers with a coating of radar-absorbing paint in order to reduce the distance at which the speed of a vehicle can be measured by a police radar unit. This is desirable because it has been found that speed measurements taken using radar at long distances can be incorrect due to limitations of the radar equipment, as well as errors in aiming it accurately. By reducing the distance at which a vehicle's speed can be measured, the use of a radar-absorbing cover reduces a motorist's likelihood of being subjected to the inconvenience and expense which can ensue from an improper charge of speeding. While a rigid cover can be painted with multiple coats of radar-absorbing paint in order to build up a series of layers whose overall thickness provides sufficient radar absorption, such coating technology does not lend itself to the production of a flexible bra due to the lack of a rigid substrate for carrying such paints.